Virtualization performance issue with KVM/Qemu after upgrade 11.3 -> 11.4

I experience severe perfornance issues with KVM/QEMU after the upgrade. My original scenario, where everything went fine, was:

  • Host: openSUSE 11.3 with latest updates
  • Guest: openSUSE 11.4 RC1
    Both have been upgraded via DVD to the 11.4 release.

After the upgrade, the erpformance issues start already with slow image generation in the virtual machine console of the virtual machine manager. Text of the boot process comes up line by line. Once the guest is up, Samba performance has dropped by a factor of 10 compared to the scenario before the upgrade.

To me it feels like an I/O issue since the machine processes of the guest and host machine are looking alright. CPU consumption does look ok to me compared to the pre-upgrade scenario (CPU idle around 60% of host and 70% of guest).

I realized, 11.4 comes with a 0.14RC1 of KVM/QEMUversion. Are there known issues or anything I can do to get back the old performance?

Thx for any support